Indeed, Pliny’s title, _Naturalis Historia_, or at least the common English translation of it, “Natural History,” has been criticized as too limited in scope, and the work has been described as “rather a vast encyclopedia of ancient knowledge and belief upon almost every known subject.”[121] Pliny himself mentions in his preface the Greek word “encyclopedia” as indicative of his scope. Nevertheless, his work is primarily an account of nature rather than of civilization, and much of its information concerning such matters as the arts and business is incidental. Most of its books bear such titles as Aquatic Animals, Exotic Trees, Medicines from Forest Trees, The Natures of Metals. After an introductory book containing the preface and a table of contents and lists of authorities for each of the subsequent books, the second book treats of the universe, heavenly bodies, meteorology, and the chief changes, such as earthquakes and tides, in the land and water forming the earth’s surface. After four books devoted to geography, the seventh deals with man and human inventions. Four more follow on terrestrial and aquatic animals, birds, and insects. Sixteen more are concerned with plants, trees, vines, and other vegetation, and the medicinal simples derived from them. Five books discuss the medicinal simples derived from animals, including the human body; and the last five books treat of metals and minerals and the arts in which they are employed. It is thus evident that in the main Pliny is concerned with natural science, and that, if his work is a mine of miscellaneous historical information, it should even more prove a rich treasure-house—“_quoniam, ut ait Domitius Piso, thesauros oportet esse non libros_”[122]—for an investigation concerned as intimately as is ours with the history of science. [Sidenote: As a source for magic.] The _Natural History_ is a great storehouse of misinformation as well as of information, for Pliny’s credulity and lack of discrimination harvested the tares of legend and magic along with the wheat of historical fact and ancient science in his voluminous granary. This may put other historical investigators upon their guard in accepting its statements, but only increases its value for our purpose. Perhaps it is even more valuable as a collection of ancient errors than it is as a repository of ancient science. It touches upon many of the varieties, and illustrates most of the characteristics, of magic. Moreover, Pliny often mentions the _Magi_ or magicians and discusses “magic” expressly at some length in the opening chapters of his thirtieth book—one of the most important passages on the theme in any ancient writer. [Sidenote: Pliny’s career.]